Electric vehicle

Abstract

To provide an electric vehicle which can avoid excessive lowering of an SOC (State Of Charge) value caused by a detection error of power consumption and a vehicle stop due to the lowering.SOLUTION: An electric vehicle 10 includes: a chargeable / dischargeable battery 102; a generator 103 which can control generated power; a drive motor 101 which drives a vehicle; and electrical appliances 105 which consume power. The electric vehicle further includes: a correction amount generation section 301 which generates a correction amount Δ increased according to a lowering amount when a state of charge value (SOC) of the battery becomes lower than a prescribed value; an addition section 302 which calculates a second power consumption value P2 by adding the correction amount Δ to a first power consumption value P1 calculated from power consumption detection values of the electrical appliances; and a control section 200 which controls the generated power by the generator on the basis of a power value including a vehicle driving power value Pd for driving the vehicle and the second power consumption value P2 and maintains the state of charge value of the battery to a prescribed value or more.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control technique for an electric vehicle that runs by driving a motor (electric motor) using electric power. [Background technology]

[0002] In electric vehicles, if the battery's state of charge (SOC) falls below a limit, the battery becomes susceptible to deterioration, so from the perspective of battery protection, it is necessary to avoid excessive drops in SOC.To achieve this, in battery power management, the power consumption of the drive motor and air conditioner, as well as that of auxiliary equipment, is detected, and the power generated by the generator and the motor torque during regeneration are controlled.

[0003] For example, when the SOC falls to the discharge prohibition level, the power generation is increased to charge the drive battery, and the dischargeable power (or output limit power) SOP (Status Of Power) out In Patent Document 1, SOP is set to zero to prevent the power generation from decreasing. out Patent Document 2 discloses a method for correcting the input power limit SOP in order to increase the generated power. in and output power limit SOP out A method is disclosed in which a correction power is added to the generated power when the difference between the actual power and the actual power becomes small. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-118558 [Patent Document 2] JP 2021-118559 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned background art is premised on accurate detection of power consumption, and cannot be an effective measure when there is a detection error. For example, the detected value of the power consumption of the auxiliary equipment may be smaller than the actual value due to insufficient sensor or calculation accuracy. If the detected value is smaller than the actual power consumption of the auxiliary equipment, the charging power of the drive battery during power generation or regenerative braking may be too small, and the remaining SOC of the drive battery may be depleted.

[0006] The above-mentioned Patent Document 1 discloses a measure to deal with transient excess discharge power, but is not suitable for correcting steady-state detection errors. in and SOP out Since the correction is performed according to the power difference between the power supply and the power source, it may not be possible to effectively prevent the SOC from decreasing.

[0007] If the power consumption of in-vehicle electronic components is not detected accurately in this way, the detected power consumption value may be lower than the actual value, resulting in an insufficient charging power for the drive battery, which may cause the actual remaining battery charge SOC to run out, increasing the possibility of the vehicle stalling.

[0008] The present invention has been devised in consideration of the above-mentioned circumstances, and an object of the present invention is to provide an electric vehicle that can avoid an excessive decrease in SOC caused by an error in detecting power consumption and the resulting vehicle stop. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, one embodiment of the present invention is an electric vehicle including a chargeable and dischargeable battery, a generator capable of controlling the generated power, a drive motor that drives the vehicle using power from the battery and / or the generator, and electrical equipment that consumes power, and is characterized by comprising: a correction amount generation unit that generates a correction amount that increases according to the amount of decrease in the state of charge value of the battery when the state of charge value of the battery falls below a predetermined value; an addition unit that calculates a second power consumption value by adding the correction amount to a first power consumption value calculated from the power consumption detection value of the electrical equipment; and a control unit that controls the power generated by the generator based on power values ​​including a vehicle drive power value for driving the vehicle and the second power consumption value, and maintains the state of charge value of the battery above the predetermined value. In addition, one embodiment of the present invention is characterized in that the correction amount is maintained at zero if the charge state value of the battery is equal to or greater than a predetermined value, and if the charge state value falls below the predetermined value, the correction amount is increased in proportion to the amount of decrease, and an upper limit value is set for the correction amount to protect against overcharging. In one embodiment of the present invention, the predetermined value is a discharge prohibition value of the battery. In one embodiment of the present invention, the first power consumption detection value of the electrical equipment has lower detection accuracy than other detection values ​​including the power consumption detection value of the drive motor. According to one embodiment of the present invention, the generator is connected to an engine, and the control unit controls the torque required for the engine and the generator. Effect of the Invention

[0010] According to one embodiment of the present invention, when the battery's state of charge value falls below a predetermined value, a correction amount that increases according to the amount of decrease in the state of charge value is generated, and this correction amount is added to the power consumption detection value of the electrical equipment.Even if the power consumption detection value of the electrical equipment is smaller than the actual power consumption (actual value), the generator's power generation can be optimized, and the battery's state of charge value can be maintained at an appropriate value to avoid vehicle stop. Furthermore, according to one embodiment of the present invention, no correction is made to the power consumption detection value of the electrical equipment until the battery's state of charge value decreases to a predetermined value, and when the state of charge falls below the predetermined value, a correction is made in proportion to the amount of decrease. As a result, when the battery's state of charge falls below the predetermined value, the amount of power generated is increased in accordance with the amount of decrease, and the battery's state of charge is quickly optimized. Furthermore, according to one embodiment of the present invention, the predetermined value that is the criterion for starting execution of the correction is the battery discharge prohibition value, so that it is possible to effectively avoid the vehicle stopping due to an insufficient state of battery charge power. Furthermore, according to one embodiment of the present invention, by correcting the power consumption detection values ​​of electrical equipment with relatively low detection or calculation accuracy, it is possible to properly maintain the battery's state of charge value and effectively avoid vehicle stoppage even in cases where the power consumption error is relatively large, such as in the case of auxiliary equipment in a vehicle. Furthermore, according to one embodiment of the present invention, the generator is connected to the engine and the generated power is controlled, so that the state of charge value of the battery can be properly maintained in a so-called hybrid vehicle, thereby preventing the vehicle from stopping. [Brief description of the drawings]

[0011] [Figure 1] 1 is a block diagram showing a schematic configuration of an electric vehicle according to an embodiment of the present invention; [Diagram 2] 2 is a functional block diagram for explaining the operation of a vehicle ECU in the electric vehicle according to the present embodiment. FIG. [Diagram 3] 3 is a graph showing an example of a correction amount Δ of a correction amount generating unit shown in FIG. 2 . [Figure 4] 4 is a time chart showing an example of the operation of the control device according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The electric vehicle 10 has a drive motor 101, a battery 102, a generator 103, an engine 104, and auxiliary equipment 105, and further includes, as control systems thereof, a vehicle ECU (Electronic Control Unit) 200, an MCU (Motor Control Unit) 201, a BMU (Battery Control Unit) 202, a GCU (Generator Control Unit) 203, an engine (ENG) ECU 204, and an auxiliary equipment ECU 205. In Fig. 1, solid lines indicate power lines and dashed lines indicate communication lines, and a circuit consisting of an inverter and a DC-DC converter is configured between the battery 102, drive motor 101, generator 103, and auxiliary equipment 105, but is omitted here.

[0013] The drive motor 101 runs using electric power to rotate the drive wheels of the electric vehicle 10, and also generates regenerative power when the electric vehicle 10 decelerates to generate regenerative braking force. The battery 102 stores electric power to run the drive motor 101. Examples of the electric power stored in the battery 102 include electric power generated by a generator 103 described below, electric power generated by regenerative power generation of the drive motor 101, and electric power supplied by connecting an external power source via a charging mechanism (not shown). In this embodiment, the description will be given assuming that the output (discharge) power from the battery 102 is positive and the input (charge) power to the battery 102 is negative.

[0014] The generator 103 is driven by the engine 104, and generates electric power to be used by the drive motor 101 and the accessories 106 of the electric vehicle 10. Surplus electric power generated by the generator 103 that is not used by the drive motor 101 and the accessories 106 of the electric vehicle 10 is stored in the battery 102. The generator 103 also generates electric power to be stored in the battery 102 when the charging rate SOC of the battery 102 becomes low. The engine 104 is an internal combustion engine that runs by burning fuel, and is connected to a rotating shaft of the generator 103. It is also possible to perform so-called parallel running, in which the engine 104 rotates the drive wheels of the vehicle 10 based on the running state of the vehicle 10.

[0015] The vehicle ECU 200 is connected to the MCU 201, the BMU 202, the GCU 203, the engine ECU 204, and the auxiliary ECU 205, and controls the entire vehicle as a control device for the electric vehicle 10. In addition, various sensors such as an accelerator pedal sensor that detects the amount of operation AP of an accelerator pedal, a brake pedal sensor that detects the amount of operation of a brake pedal, and a vehicle speed sensor that detects the traveling speed V of the electric vehicle 10 are connected to the vehicle ECU 200.

[0016] The MCU 201 controls the drive motor 101, the BMU 202 controls the battery 102, the GCU 203 controls the generator 103, the engine ECU 204 controls the engine 104, and the auxiliary ECU 205 controls the auxiliary devices 105. The auxiliary devices 105 include electric devices that consume power, such as an electric compressor for an air conditioner, front / rear glass heaters, heated door mirrors, and various lamps. As will be described later, the BMU 202 outputs information such as the SOC and temperature of the battery 102 to the vehicle ECU 200 as the battery state amount. The auxiliary ECU 205 also calculates the power consumed by the auxiliary devices 105 using sensor values ​​such as a DC-DC converter, and outputs the calculated value P1 to the vehicle ECU 200.

[0017] The vehicle ECU 200 includes a processor such as a CPU (Central Processing Unit), a ROM (Read-only memory) that stores a control program executed by the processor, a RAM (Random access memory) as a working area for the control program, an interface with peripheral circuits, etc. The control function according to this embodiment can be implemented by executing a program on the processor of the vehicle ECU 200.

[0018] The vehicle ECU 200 that functions as a control device according to this embodiment will be described in detail below. This embodiment is applicable to on-board electrical devices that have lower power consumption detection accuracy than the drive motor 101 and the like, but here, the auxiliary devices 105 are shown as an example of such on-board devices. This is because the detected power consumption of the auxiliary devices 105 may be smaller than the actual value due to insufficient sensors or calculation accuracy. According to this embodiment, as described in detail below, the calculated power consumption of the auxiliary devices 105 is corrected according to the SOC of the battery 102, thereby preventing the SOC from decreasing beyond the limit or increasing the SOC.

[0019] 2, the vehicle ECU 200 is equipped with the following functions. A correction amount generating unit 301 generates a correction amount Δ, which will be described later, and an adding unit 302 adds the correction amount Δ to an auxiliary power consumption calculation value P1 calculated from a sensor detection value, and outputs auxiliary power consumption P2 (=P1+Δ). An adding unit 303 adds the vehicle driving power Pd, the auxiliary power consumption P2 input from the adding unit 302, and the target charging power Ptc, and generates a target generation power Ptg, which is output to a limiting unit 305. Here, the vehicle driving power Pd changes depending on the accelerator operation AP and the vehicle speed V, and the target charging power Ptc is set depending on a decrease in the SOC of the battery 102.

[0020] Furthermore, the adding unit 304 adds the motor power consumption Pm, the auxiliary power consumption P2, and the chargeable power Pcp to generate the upper limit power generation Pug and outputs it to the limiting unit 305. Here, the motor power consumption Pm is the power actually consumed by the drive motor 101, and the chargeable power Pcp varies depending on the temperature of the battery 102. The limiting unit 305 outputs the smaller of the target power generation Ptg and the upper limit power generation Pug as the required power generation Prg, and the required power generation Prg is reflected in the torque required for the engine 104 and the generator 103.

[0021] When the motor power consumption Pm becomes larger than the required power generation Prg during high-load driving on an uphill road or a highway, the drive motor 101 is supplied with power from the generator 103 as well as the battery 102, and the battery 102 enters a discharged state. If high-load driving continues, charging cannot be performed according to the target charging power Ptc, and the opportunities for charging the battery 102 decrease. In addition, when the battery 102 becomes cold, the chargeable power Pcp decreases, the upper limit power generation Pug decreases, and the required power generation Prg is limited, thereby reducing the opportunities for charging the battery 102. Furthermore, if the auxiliary power consumption calculation value P1 is smaller than the actual value P0, the target power generation Ptg and the upper limit power generation Pug decrease, so that the motor power consumption Pm becomes relatively large, and the opportunities for charging the battery 102 decrease. These conditions combine to reduce the opportunities for charging, and the SOC decreases. When discharging the battery 102 is prohibited due to a decrease in SOC, the output of the drive motor 101 is limited so that the vehicle drive power Pd and the motor power consumption Pm match. When the SOC drops to the discharge prohibition level due to discharge, the target power generation Ptg is calculated using the auxiliary power consumption P2 (=P1+Δ) obtained by adding a correction amount Δ to the auxiliary power consumption calculated value P1, as described below. Therefore, the power generation can be increased by the correction amount Δ, thereby preventing an excessive drop in the SOC.

[0022] 2 are implemented by executing a program on the processor of the vehicle ECU 200, and existing control configurations can be used for the functions of the adders 303 and 304 and the limiter 305. Therefore, the characteristic functions of this embodiment can be realized by the correction amount generator 301 and the adder 302. The characteristic functions will be described below.

[0023] 3, when the SOC of the battery 102 falls below a predetermined level, the correction amount generator 301 increases the correction amount Δ according to the amount of fall. The correction amount Δ for the SOC increases as the SOC falls below the predetermined level, thereby increasing the amount of power generation by the engine, preventing a fall in the SOC or quickly raising it to above the predetermined level.

[0024] 3, if the predetermined level is a preset battery discharge prohibition SOC, when the SOC is equal to or higher than the discharge prohibition value B1, the correction amount Δ is set to 0 and the auxiliary power consumption is not corrected (region R1). When the SOC falls below the discharge prohibition value B1, the correction amount Δ is increased according to the amount of SOC decrease (region R2). Here, the correction amount Δ is increased in proportion to the amount of SOC decrease from the discharge prohibition value B1. However, the correction amount Δ is limited to a range in which the battery 102 is not overcharged, and here, Δ UL Therefore, the correction amount Δ is the upper limit Δ UL Even if the SOC falls below the SOC value B2, the correction amount Δ does not increase any further (region R3).

[0025] In this way, even if the detection value P1 of the power consumption of the auxiliary equipment 105 is smaller than the actual power consumption (real value) P0, by adding the correction amount Δ to the detection value P1 of the power consumption of the auxiliary equipment, the generated power can be optimized and an excessive decrease in the SOC of the battery 102 can be avoided. Hereinafter, the operation of the electric vehicle 10 to which the correction control according to this embodiment is applied will be described with reference to Fig. 4.

[0026] As shown in Fig. 4(B), when the calculated value P1 of the power consumption of the auxiliary equipment 105 is smaller than the actual auxiliary equipment power consumption P0 due to insufficient sensors or calculation accuracy, the vehicle driving power Pd and the target charging power Ptc are added to the underestimated auxiliary equipment power consumption calculated value P1 to generate the target power generation Ptg, and power is generated based on the calculated value. As a result, the charging power of the battery 102 decreases, and the target charging power Ptc exceeds the chargeable power Pcp, causing the SOC of the battery 102 to tend to discharge, to decrease to the discharge inhibition value B1 as shown in Fig. 4(A).

[0027] If the SOC of the battery 102 drops to the discharge inhibition value B1 at time t1, the vehicle ECU 200 (correction amount generating unit 301) increases the correction amount Δ according to the amount of SOC drop below the discharge inhibition value B1, as shown in Fig. 3. As a result, the correction amount Δ is added to the auxiliary power consumption calculation value P1, increasing the auxiliary power consumption P2, and the target generation power Ptg is generated by adding the vehicle driving power Pd and the target charging power Ptc to the increased auxiliary power consumption P2. Therefore, as shown from time t1 to t2 in Fig. 4, the increase in the auxiliary power consumption P2 eliminates the underestimation of the auxiliary consumption calculation value P1, and the engine generation power increases, which causes the battery 102 to enter a charging state and the SOC to be restored to and maintained at the discharge inhibition level.

[0028] As described above, according to this embodiment, even if the detection value P1 of the power consumption of the auxiliary equipment 105 is smaller than the actual power consumption (actual value) P0, the correction amount Δ is added to the detection value P1 of the power consumption of the auxiliary equipment, thereby optimizing the generated power and preventing the SOC of the battery 102 from decreasing excessively.

[0029] Conventionally, as shown in Fig. 4(B), engine power generation is performed with the underestimated auxiliary power consumption P1, so the battery 102 remains in a discharged state and the SOC continues to drop beyond the discharge prohibition value. As a result, the remaining charge of the battery 102 is depleted at time t3 shown in Fig. 4, causing high voltage cutoff and stopping the vehicle 10.

[0030] In contrast, according to this embodiment, when the SOC drops to the discharge prohibition level, a correction amount Δ is added to the detected auxiliary power consumption P1 to increase the engine power generation amount, thereby effectively avoiding the vehicle stopping as in the conventional example. [Explanation of symbols]

[0031] 10 Electric vehicles 101 Drive motor 102 Battery 103 Generator 104 Engine 105 Auxiliary Equipment 200 Vehicle ECU (Electronic Control Unit) 201 Motor Control Unit (MCU) 202 Battery Control Unit (BMU) 203 Generator Control Unit (GCU) 204 Engine Control Unit (ENG ECU) 205 Auxiliary Control Unit (Auxiliary ECU) 301 Correction amount generation unit 302~304 Addition section 305 Restrictions

Claims

1. An electric vehicle including a chargeable and dischargeable battery, a generator capable of controlling generated power, a drive motor that drives the vehicle using power from the battery and / or the generator, and electrical equipment that consumes power, a correction amount generating unit that generates a correction amount that increases according to an amount of decrease in the state of charge value of the battery when the state of charge value of the battery decreases below a predetermined value; an adder that calculates a second power consumption value by adding the correction amount to a first power consumption value calculated from the power consumption detection value of the electrical device; a control unit that controls the power generated by the generator based on a vehicle driving power value for driving the vehicle and a power value including the second power consumption value, and maintains a state of charge value of the battery at or above the predetermined value; An electric vehicle comprising:

2. 2. The electric vehicle according to claim 1, wherein the correction amount is maintained at zero if the state of charge value of the battery is equal to or greater than a predetermined value, and the correction amount is increased in proportion to the amount of decrease if the state of charge value of the battery falls below the predetermined value, and an upper limit value is set for the correction amount for overcharge protection.

3. 3. The electric vehicle according to claim 1, wherein the predetermined value is a discharge prohibition value of the battery.

4. The electric vehicle according to any one of claims 1 to 3, characterized in that the first power consumption detection value of the electrical equipment has a lower detection accuracy than other detection values ​​including a power consumption detection value of the drive motor.

5. 5. The electric vehicle according to claim 1, wherein the generator is connected to an engine, and the control unit controls a required torque for the engine and the generator.

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